High-resolution electron microscopy (HREM) examination of dislocation core structure in B2 FeAl single crystals

Stoichiometric Fe-50at.%Al and iron-rich Fe-40at.%Al single crystals oriented near [001] have been deformed in compression at 873 K to approximately 5% plastic strain. Conventional diffraction contrast transmission electron microscopy (TEM) has been used to characterize the dislocation structures in these materials. The observed dislocations are predominantly 〈001〉{001} prismatic edge dislocations, with a small number of 〈111〉 screw dislocations. The atomic level details of the core structures of these dislocations have been examined using phase contrast TEM and high-resolution electron microscopy (HREM). Dislocations with both glide and climb dissociated core structures have been observed. The implications of these structures on the mechanical behavior (at both low and elevated temperatures) are discussed.